Horseshoe-magnet



F. BILLON AND J. BOHLI.

SESHOE MAGNET.

APPL 0N FILED AUG.22. 1919.

Patented Dec. 27, 1921.

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citizen of the Swiss FREDERIC BILLON AND JACQUES BOHLI, 0F

T0 FIRM SCINTILLA,

SOLOTHURN, SWITZERLAND, ASSIGNORS OF SOLOTHURN, SWITZERLAND.

HORSESHOE-MAGNET.

Specificationvv of Letters Patent.

' Patented Dec. 27,1921.

Application led August 22; 1919. Seria'l No. 319,147.

T o all whom t may concern Be it known that we, FREDERIC BILLoN, a Republic, residing at Solothurn, Switzerland, and J ACQUEs BoHLI, a citizen of the Swiss Republic, residing at Obac'k, Solothurn, Switzerland, have inveited certain new and useful Improvements in Horseshoe-Magnets, (for which I have filed an application in Switzerland, August 29, 1918; Germany, Sept. 3, 1918, and Austria, July 1, 1919,) of which the following is a specification.

This invention has for its object to' provide an improved horseshoe magnet-,of the class of horseshoe magnets having a, subperipheral surfacestantially cylindrical more particularly designed for magnetoelect'ric ignition machines. 'A magnet of this class is made of a cylindrical piece of isteel which is cut with a parallel-sided slot that contains the shaft, and beginning at one end, sto s short of the other end of the said piece. or the purpose of enabling this slot to be cut more readily with a milling cutter, and for the purpose ing the path ofthe lines of force in the steel of the magnet which is desirable more .particularly in the case of short magnets,

an improved magnet according to this invention is formed at the end of the slot nearest its yoke, with a hole having a diameter greater thanthe width of the slot. The axis of this hole is parallel to the sides of the slot and at right angles to the axis of the magnet.

If the power of the magnet is determined on the one hand by its length and on the other hand by its cross-section, a definite ratio is found between the length and crosssection which is the most favorable for making the best use of the material as regards its magnetic properties.4 The form in which the magnet is used of course plays an important part as regards the magnetic distribution conditions. But it is possible to determine for each case the most favorable ratio of length and cross-section for a magnet. Where a definite s aeg is provided for the magnet it is possible that, for instance, the horseshoe ing the best use of the material for the magalso of lengthen- Vtion on line -y is shape allows of maknet. This is more especially the case when the .space available has a relatively large cross-section and small length. lhe present invention makes it possible 1n this case that a given space is available for giving the horse-shoe magnet such form that the ratio/of cross-section to length is the most favorable although for the length when employing the vusual shapeV of horseshoe magnet the space is too small. n the accompanying drawings which illustrate diagrammatically a constructional example vof the improved magnet, e

lgigure 1 shows a front elevatio-n thereof an Fig. 2 a cross sectional plan on the line -'g/ of Fig. l'

The improved magnet N. J. S. consists of a cyllndrlcal vpiece of steel bent into the form as shown with a. parallel opening a between the leg members. A. circular bore b isprovided concentric with the outer con-A tour of the magnet where it is bent into a semi-circular form as shown at J. It will be seen from the diagram, in which a dotted line at the apex of the parallel members 0f the magnet shows the circular bore b is formed that the cross secyoke J as in the leg members.

Upon further reference to the drawings the curved lines c, d represent the lines of force, the normal path of line of force in thev usual form is represented partly by a full line and partly by a dotted line, the direction of the lines of force being indicated by the arrow heads; the line is practically central with the magnet structure.

vIn the present invention the line of force is shown by the full line in which the curved part thereof follows a central path between the outer and inner faces of the magnet and owing to the section of the magnet at the yoke thereof being less than in the leg portion the path of the lines .of force as indicated by the line c embraces a greater length so that by this construction a greater effect is thereby` obtained in the magnetic effect. i'

What we claim is A horse-shoe magnet constructed of not the same at they magnet before the Va cylindrical steel bar bent to form a. direction perpendicular looth to said axis U-shaped cylindrical body, a parallel-sided and said slot sides. slot symmetrically bifurcatingg;V said body In testimony whereof We have signed from one end and terminating in a hole in our names to thi s"speciication.

5 the yoke of said body parallel to said slot A and perpendicular t0 said axis, said hole FREDERIC -BILLON being of greater Width than said slot in a JAK. BOHLI. 

